Air-fuel ratio regulation system for combustion engine

摘要

The system includes air-fuel ratio sensors (26, 27) arranged in an up-stream and a down-stream side of a catalytic converter (13), and a regulation arrangement (30) which regulates an air-fuel ratio of a mixture on a nominal air-fuel ratio. An arrangement detects a response speed of the air-fuel ratio in the up-stream side with respect to the air-fuel ratio in the down-stream side, and an adjustment arrangement adjusts a feedback amplification accordingly. The system includes an air-fuel ratio sensor (26) which is arranged at an up-stream side of a catalytic converter, and an air-fuel ratio sensor (27) arranged at a down-stream side of the catalytic converter. A regulation arrangement regulates an air-fuel ratio of a mixture on a nominal air-fuel ratio based on the air-fuel ratio determined by the up-stream air-fuel ratio sensor, whereby a feedback amplification is adjusted in dependence on the air-fuel ratio determined by the down-stream air-fuel ratio sensor. A response speed detection arrangement detects a response speed of the air-fuel ratio in the up-stream side with respect to the air-fuel ratio in the down-stream side, and an amplification adjustment arrangement adjusts the feedback amplification in response to the detected response speed.